package Day11;

import java.util.Scanner;
// 1:无需package
// 2: 类名必须Main, 不可修改
/**
 * 2021Java真题:整数分解
 * https://www.lanqiao.cn/problems/2384/learning/
 */
public class Main3 {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        //在此输入您的代码...
        long[][] dp = new long[2022][6];
        for(int i = 1; i < 2022; i++){
          dp[i][1] = 1;
        }

        for(int i = 2; i < 2022; i++){
          for(int j = 2; j < 6; j++){
            dp[i][j] = dp[i - 1][j] + dp[i - 1][j - 1];
          }
        }
        System.out.println(dp[2021][5]);
        scan.close();
    }
}